Cyclic adsorption process for removal and/or recovery of h2s from natural gas



1 6 0 W mm k v JR MW 2 h N S 6 July 16, 1957 E. B. MILLER CYCLICADSORPTION PROCESS FOR REMOVAL AND RECOVERY OF H 5 FROM NATURAL GASFiled Oct. 5, 1956 v B 6 2 J, 8 Z 7 5 r j w 0 1 1 Q!) WLW f y a A V! IIIIII ILPLN IIWII III IIIIILIII IIwI l M N m E E 0 0 a w M w M W W m a Wa. e e a e p m p W m w m 1 r w A A A 5 7 0 0 0 7 G e c w e N A H A w m wm w F 3 r||||1|1 -|||l M|| |||||m1 |I||m| L m 6 J M 9 W U A Q E 9 Z Mlwlv WWW a V E I 2 H 4 3 A A c 4 INVENTOR 58/1 1557 5. M/ZZEB ATTORNEYJuly 16, 1957 E, MILLER 2,799,361

CYCLIC ADSORPTIQN PROCESS FOR REMOVAL AND/OR RECOVERY OF H25 FROMNATURAL GAS Filed Oct. 5, 1956 6 Sheets-Sheet 2 INVENTOR yin/575 mum WJa ATTORNEYS July 16, 1957 E B 2,799,361

CYCLIC ABSORPTION. PROCESS FOR REMOVAL AND/OR RECOVERY OF H25 FROMNATURAL GAS Filed Oct. 5, 1956 6 Sheets-Sheet 3 4 7 INVENTOR ATTORNEYS2,799,361 ABSORPTION PROCESS FOR REMOVAL AND/OR RECOVERY OF H25 FROMNATURAL G E. B. MILLER July 16, 1957 CYCLIC Filedoct. 5, 1956 6Sheets-Sheet 4 I N VENTOR ATTORNEYS MILLER 2,799,361

.FOR REMOVALSAND/OR I July 16, 1957 M NATURAL GA 6 Sheets-Sheet 5 E. B.CYCLIC ABSORPTION OCESS RECOVERY OF FRO Filed Oct. 5, 1956 ATTORNEY July16, 1957 E B M LLER 2,799,361

l CYCLIC ADSORPTION PROCESS FOR REMOVAL AND/OR (rSheets-Sheet 6 RECOVERYOF H 3 FROM NATURAL GAS Filed Oct. 5, 1956 FIG. H.

F 16. IO.

- INVENTOR .m/msra. MIL L 5? ATTORNEYS United States Patent CYCLICABSORPTION PROCESS FOR REMOVAL gig/OR RECOVERY OF H FROM NATURAL ErnestB. Miller, Houston, Tex., assiguor to Jefferson Lake Sulphur Company,New Orleans, lam, a corpora tion of New Jersey Application October 5,1956, Serial No. 614,288 8 Claims. (Cl. 183-1142) This invention relatesto adsorption processes for treating fluids to remove and/ or recoverparticular constituents of the fluid and has more particular referenceto cyclic adsorption processes of the type comprising an adsorptioncycle in which the fluid being treated passes through one or moreadsorption stages of the adsorber; and an activation cycle employing acaptive activation gas recycled through a heater and the activationstage of the adsorber.

One object of the present invention i to provide a novel and improvedcyclic adsorption process as characterized above including three purgingcycles, a first purging cycle preceding the activation cycle and asecond and third purging cycles following in succession after theactivation cycle so as to permit a high concentration of desorbedproducts in the recycling captive activation gas by preventing thedilution of the activation gas by slippage gas and also preventing theloss of desorbed products by slippage of the activation gas into theoutgoing efiluent stripped gas.

Another object of the present invention is to provide a novel andimproved adsorption process for recovering constituents from fluids ascharacterized above, which is characterized by maintaining at least onebed of adsorbent material in each of a plurality of stages; continuouslyheating and recycling captive activation gas through at least one orsaid stages to gradually build up its concentration of desorbed productsto a high concentration by volume; continuously directing a flow of afirst purging medium through at least another one of said stages topurge the stage; continuously directing a flow of a second purgingmedium through at least another one of said stages to purge the stage;continuously directing the flow of the fluid to be treated through theremainder of said stages so that substantially all of the particularconstituent content of the fluid will be adsorbed by the adsorbentmaterial therein; periodically shifting the relative position of theparticular adsorbent beds and the particular flow of fluids in each ofsaid stages so that each stage becomes, in succession, a first purgingstage, an activation stage, a second purging stage and an adsorptionstage; continuously diverting a portion of the recycling activation gasfor use as the first purging medium and continuously diverting a portionof the flow of the stripped efliuent fluid from the last adsorptionstage for use as the second purging medium; continuously directing theeflluent fluid from the first purging stage back into the flow of thefluid being treated on its way to the adsorber; continuously directingthe flow of the eflluent fluid from the second purging stage back intothe recycling activation gas; continuously withdrawing a portion of thecaptive activation gas from its recycling path after its concentrationof desorbed products has built up to a predetermined degree, as thefinished product.

A further and more limited object of the present invention is to providea novel and improved process for removing and recovering HzS fromnatural gas from which water vapor and condensable hydrocarbons havepreviously been removed therefrom including the purging steps ascharacterized above.

Other objects and advantages of the invention will appear 1n thefollowing specification when considered in connecticn with theaccompanying drawings, in which:

r 1g. 1 15 a schematic view showing one embodiment of apparatus and thearrangement thereof for carrying out tne method of the present inventionand the flow of the various fluids therethrough;

Fig. 2 is a side elevational view of the adsorber shown inFig. 1;

Fig. 3 is a plan view of the apparatus shown in Fig. 2;

Fig. 4 is a vertical sectional view taken on the line 44 of Fig. 3, butomitting the driving apparatus;

Fig. 5 is a horizontal sectional view taken on the line 5-5 of Fig. 4;

Fig. 6 is a fragmentary sectional view taken on the line 6-6 of Fig. 4,showing the manner of bracing the upper ends of the elongated adsorbentmaterial containing vessels;

Fig. 7 is a fragmentary sectional view taken on the line 77 of Fig. 4,showing the manner of supporting the lower ends of the elongatedadsorbent material containing vessels;

Fig. 8 is a horizontal sectional view taken on the line 88 of Fig. 4;

Fig. 9 is a detail sectional view, taken on the line 9-9 of Fig. 8;

Fig. 10 is a vertical sectional view, with parts broken away, of theadsorbent material containing vessels shown in Fig. 4, showing thecontainers for holding the adsorbent material mounted therein; and aFig. 11 is a plan view of the container shown in Fig. 10.

The present invention provides a novel and improved process for removingand/or recovering particular constituents from fluids. The process is acontinuous cyclic adsorption process employing an adsorber in which atleast one bed of adsorbent material is maintained in a plurality ofstages and, in general, comprises an adsorption cycle in which acontinuous flow of the fluid being treated is directed, under highpressure, through one or more adsorption stages so that substantiallyall of the particular constituent content of the fluid which is to beremoved will be adsorbed by the beds of adsorbent material in theadsorption stages; an activation cycle in which a flow of a captiveactivation medium, under high pressure, is continuously recirculatedthrough a heater and an activation stage so that the concentration ofdesorbed products is built up to a high concentration by volume; aplurality of purging cycles to prevent dilution of the recyclingactivation medium, including a first purging cycle in which a portion ofthe activation medium is continuously diverted from its recycling pathand passed into a purging stage immediately preceding the activationstage, called the first purging stage, with the eflluent fluid from thefirst purging stage passing into the flow of the fluid being treated onits way to the first adsorption stage, and a second purging cycle inwhich a portion of the effluent stripped fluid from the last adsorptionstage is continuously diverted and passed into a purging stageimmediately following the activation stage, called the second purgingstage, with the effluent fluid from the second purging stage passinginto the flow of the recycling activation medium; the periodicalshifting of the relative positions of the particular adsorbent materialand the particular flow of fluid through each stage, either by movingthe beds successively through the stages or by shifting the flows offluid through the several stages, so that each stage becomes, insuccession, a first purging stage, an activation stage, a second purgingstage and an adsorption stage; and a constituent product recovery cyclein which a portion of the recycling activation medium, after itsconcentration of desorbed products has built up to a predeterminedconcentration by volume, is continuously withdrawn, as the finishedproduct.

While the novel and improved process of the invention may be employed toremove and/ or recover various constituents from various fluids it isparticularly adapted for removing and recovering HzS from natural gasand such a process will hereinafter be described, and while any suitableusual type of adsorption apparatus may be employed to practice theprocess of the present invention, for purpose of illustration, theprocess will be described as carried out by employing a rotary type ofadsorber in which a plurality of elongated upright closed vesselscontaining adsorbent material are rotated directly in succession andsubstantially continuously through the various stages of the adsorber.

Referring now to the drawings, there is shown, in Fig. 1, one embodimentof apparatus and the arrangement thereof for carrying out the method ofthe present invention. The apparatus shown includes a seven-stage rotaryadsorber 1, three stages of which are employed as adsorption stages;three stages of which are employed as purging stages; and one stage ofwhich is employed as an activation stage; a pair of inter-coolers 2 and2' employed to cool the gas being treated between the adsorption stages;a heater 3 employed to heat the activation gas used in the activationstage; a fan or blower 4 for recirculating the activation gas throughthe activation stage; and a blower 4' for circulating the purging mediumthrough the second and third purging stages.

The natural gas from which substantially all Water vapor and condensablehydrocarbons have previously been removed therefrom, is delivered, athigh pressure from the usual compressor or source of supply (not shown)to the first adsorption stage of the adsorber by means of a pipe line 5.The gas passes through the first adsorption stage of the adsorber, wheresome of the H28 is adsorbed. From the first adsorption stage of theadsorber the gaseous mixture passes through pipe line 6 and theintercooler 2 to the second adsorption stage of the adsorber. Afterpassing through the second adsorption stage of the adsorber, whereadditional HzS is adsorbed, the gaseous mixture passes through pipe line7 and intercooler 2' to the third adsorption stage of the adsorber.After passing through the third adsorption stage of the adsorber, theH23 stripped gas passes through pipe line 8 to its various points ofuse.

The captive activation gas is heated in the heater 3 to a temperature offrom 300 F. to 400 F., and from the heater passes through a pine line 9into the activation stage of the adsorber. The heated gas passesupwardly throu h the activiation stage, desorbing the accumulated H28from the adsorbent material therein. The heated gas and the H2S desorbedfrom the adsorbent material pass through a pipe line 10 to the blower 4,from which they pass through pipe line 11 back to the heater 3.

The captive stream of gas in the activation system is recirculated bymeans of the blower 4, through the heater 3 and the activation stage ofthe adsorber. This recirculation process is continuous. Therecirculating captive stream of activation gas is allowed to becomehighly concentrated in desorbed HzS by passing directly from theactivation stage outlet back to the heater without any intermediatecooling.

The vessels which contain the silica gel beds are rotated so that eachvessel passes in succession through the various stages of the adsorber.As the vessels move through each stage they are filled with theparticular gas flowing through the stage and carry this gas into thenext or succeeding stage in their rotary movement. This carrying of gasfrom one stage to the other by the vessels is called slippage.

In order to prevent the slippage gas from the first adsorption stage,which would consist of the gaseous mixture being treated, from beingcarried over into the activation stage and dilute the highlyconcentrated recycling activation gas, a purge stage is interposedbetween the first adsorption stage and the activation stage and calledthe first purge stage. A portion of the captive activation gas flowingto the heater 3 through pipe line 11 is diverted through pipe line 12for use as the purging gas in the first purging stage. The eflluent gasfrom the first purging stage passes through pipe line 13 back into pipeline 5 to join the flow of the gas being treated on its way to the firstadsorption stage of the adsorber. This permits the purging gas in thefirst purging stage to push the slippage gas in the first purging stageback into the incoming gaseous mixture being treated on its way to thefirst adsorption stage of the adsorber. And, as the gas used as thepurging gas in the first purging stge is obtained by continuouslydiverting a portion of the recycling activation gas from its recyclingpath, the slippage gas from the first purging stage into the activationstage would consist of activation gas so that the recycling captiveactivation gas would not be diluted.

Also, in order to prevent the slippage gas from the activation stage,which is rich in HzS from being carried over into the third adsorptionstage, where it would pass out of the adsorber with the outgoingstripped gas, two purging stages are interposed between the activationstage and the third adsorption stage, called the second purge stage andthe third purge stage. Stripped gas diverted from the eflluent strippedgas from the third adsorption stage is employed as the purging gas forthe second and third purge stages.

A portion of the effluent stripped gas flowing from the third adsorptionstage of the adsorber through pipe line 8 is diverted through pipe line14 to the blower 4', from which it passes through pipe lines 15 and 16,into the sec- 0nd and third purging stages, respectively, of theadsorber. The effluent gas from the second purging stage passes throughpipe line 17 into pipe line 10, where it joins the recycling activationgas. The eflfluent gas from the third purging stage passes through pipeline 18 and pipe line 13 back into the pipe line 5 to join the gas beingtreated on its way to the first adsorption stage of the adsorber.

The purging gas in the second purging stage pushes the slippage gas fromthe activation stage through pipe line 17 into pipe line 10, where itrejoins the recycling activation gas, while the purging gas in the thirdpurging stage pushes the slippage gas from the second purging stagethrough pipe line 18 into pipe line 13 through which it passes to jointhe incoming stream of the gaseous mixture being treated on its way tothe first adsorption stage of the adsorber. The employment of the threepurging stages, as above outlined, provides for complete purging of theadsorbent material while preventing dilution of the activation gas, thuspermitting the building up of a high concentration by volume of desorbedproducts in the recycling activation gas.

After the concentration of H28 in the recycling activation stream hasreached a suitable high value, a portion thereof is continuouslydiverted and passes through pipe line 19 to storage or to its variouspoints of use.

While any suitable type of rotary adsorber may be employed to practicethe method of the present invention, the adsorber illustrated isgenerally similar to the fluid treating apparatus shown in my Patent No.2,751,033 issued June 19, 1956, for Fluid Treating Apparatus.

As shown in Figs. 2 to 11, inclusive, the adsorber com prises anelongated upright cylindrical pressure vessel 20 having flangedvertically aligned circular openings 21, 22 in its top and bottom walls,respectively, closed by top and bottom flanged cover plates 23, 24removably secured to cover said openings, as by bolting; suitableframework, indicated at 25, for supporting the vessel 20 in an uprightposition; a rotatable vertical shaft 26 extending through the pressurevessel 20 with its upper end journaled in a 5 suitable cap bearingcarried by the upper closure member 23 and with its lower endextendingthrough a suitable shaft seal,.secured to the bottom of the lowerclosure member 24; a vertical shaft 27 coupled to the bottom end of theshaft 26 and connected to suitable differential gearing, indicated at28, driven by a motor 29; a support disc 30 fixedly mounted on the shaft26 for rotation therewith within said pressure vessel [and providingsupport for a plurality of elongated fluid treating material containingcylindrical vessels 31; upper and lower distributive assemblages,indicated generally at 32, 33, each assemblage comprising an annularstationary member 34 having a plurality of compartments or manifoldsformed therein, a tube sheet disc valve 35 slidably mounted on the shaft26 for rotation therewith, a spring support disc 36 fixedly mounted. onthe shaft 26 and supporting a plurality of coiled springs 37 whichengage the tube sheet disc valve 35 and tightly press it against theopen end of the annular stationary member 34; a plurality of flexiblepipes 38, each connectingthe upper end portion of one of the vessels 31and the tube sheet disc valve 35 of the upper distributive assemblage; aplurality of flexible pipes 39, each connecting the lower end portion ofone of the vessels 31 and the tube sheet disc valve 35 of the lowerdistributive assemblage, a plurality of inlet-outlet conduits, sevensuch being shown, 40, 41, 42, 43, 44, 45 and 46, connected to theannular stationary member 34 of the upper distributive assemblage andextending upwardly through the upper cap closure member 23, for. theingress and egress of fluids to and from the upper stationary member 34;and a plurality of inlet-outlet conduits, seven such being shown, 46,41, 42', 43', 44', 45' and 46, connected to the annular stationarymember 34 of the lower distributive assemblage and extending downwardlythrough the lower cap closure member 24 for the ingress and egress offluids to and from the lower stationary member 34.

The cylindrical pressure vessel 20 and the cap cover members 23, 24 arepreferably made of heavy boiler plate. The flanges formed on theperipheries of the openings 21, 22 of the vessel 20 and the peripheriesof the cap cover members 23, 24 are preferably formed of heavy ironrings, rectangular in cross section and are welded to the peripheraledges of the openings and the cover plates, as indicated at 47.

The shafting 26, preferably and as shown, is formed of three sections,an upper section 48, an intermediate section 49, and a lower or bottomsection 50. The upper and lower sections 48 and 50 consist of solid rod,round in cross section. The intermediate section 49 consists of a hollowpipe having an internal diameter considerably larger than the diametersof the upper and lower sections.

The upper section 48 has its upper end journalled in a suitable capbearing 51 carried by the upper cover member 23 and its lower endsupported in a support bushing 52 mounted in the upper end of theintermediate section 49 with a pin 53 passing through the two sectionsand the bushing for rigidly and detachably securing the two sectionstogether.

The bottom section St) has its upper end engaged in a support bushing 54mounted in the lower end of the intermediate section 49 with a pin 55passing through the two sections and the bushing for rigidly anddetachably securing the two sections together, and with its lower endextending through the lower cover. member 24 and a suitable shaft seal.56 and coupled to the upper end of the shaft 27.

The support disc 30 which supports the cylindrical vessels 31 iscomposed of two semi-annular fiat pieces 57, the inner adjacent straightedges of which are provided with flanges which are bolted together toform the complete disc. This is to permit of assembling the disc withinthe pressure vessel' 20.

The disc, 30 (see Figs. 4 and 7) is fixedly secured, as. by bolting, toa collar 53 fixedly secured to the intermediate section 49 of the shaft26, so that the disc will rotate with the shaft. The outer peripheraledge portion of the disc 30 is supported bymeans of a plurality ofsupporting links or arms 59, each having its upper end bolted to one ofa plurality of circumferentially spaced lugs 60 carried by a collar 61fixedly secured to the intermediate section 49 of the shaft 26 and itslower end bolted to one of a plurality of circumferentially spacedupstanding lugs 62 securedto the upper surface of the disc 30.

The vessels 31 are supported by the disc 30, as by means of a pluralityof supporting links or arms 63 in the form of short sections ofstructural angles, each arm 63 having its outer end portion fixedlysecured to the bottom and one side of one of said vessels 31, as bywelding, and its inner end portion fixedly secured, as by bolting, toone of a plurality of circumferentially spaced dependent lugs 64, in theform of short sections of I-beams, welded tothe under surface of thedisc 30 (see Figs. 4 and 7).

Means may be. provided for holding the cylindrical vessels 31 in theirupright position encircling the shaft 26. In the particular embodimentof the invention illustrated, such means are. shown as comprising a disc65 composed of two semi-annular flat pieces 66, 66, the inner adjacentstraight edges of which are provided with flanges which are boltedtogether to form the complete disc. This is to permit of assembling thedisc within the pressure vessel 20. The disc 65 (see Figs. 4 and 6) isfixedly secured, as by bolting, to a collar 67 fixedly secured to theintermediate section 49 of the shaft 26, so that the disc will rotatewith the shaft. The upper end portions of the vessels 31- are held intheir upright position by the disc 65, as by means of a plurality ofbracing strips or arms 68 in the form of short sections of structuralangles. Each arm 68 has its outer end bolted to a lug 69 welded on theouter surface of one of the vessels 31 and its inner end portion fixedlysecured, as by bolting, to the upper surface of the disc 65.

The upper and lower distributive assemblages 32, 33 are identical inconstruction and, as shown in Fig. 4, each comprises an annulartrough-shaped stationary member 34 having a plurality of compartments ormanifolds formed therein; a tube sheet disc valve 35 slidably mounted onthe shaft 26 for rotation therewith; and a spring support disc 36fixedly mounted on the shaft 26 and supporting a plurality of coiledsprings 37 which engage the tube sheet disc valve 35 and tightly pressit against the open end of the annular stationary member 34.

The upper and lower annular stationary members 34- are identical inconstruction and, as shown in Figs. 4, 5, 8 and 9, each is formed in theshape of an annular trough having an annular top (or bottom) wall 70 andannular side walls 71, 72 (see Figs. 4 and 9).

The member 34 is divided into a plurality of compartments or manifolds,as by means of a plurality of circumferentially spaced pairs of wallmembers 73 extending transversely of the member 34 and having their top(or bottom) and side walls welded to the top (bottom) and side walls ofthe member 34 to form gas-tight joints. Seven such compartments ormanifolds are shown and, for the purposes of clarity of description,designated manifolds a, b, c, d, e, f and g, respectively. See Fig. 8.

The upper member 34 of the upper distributive assemblage 32 is heldstationary relative to the rotation of the shaft 26 and the upper tubesheet disc valve 35 by the upper inlet-outlet conduits 40, 41, 42, 43,44, 45, and 46, which are welded to the upper cap closure member 23 andhave their lower ends connected, as by welding, to the manifolds a, b,c, d, e, f and g, respective-v ly, in the upper member 34 to providecommunication therewith.

The lower member 34 of the lower distributive assemblage is heldstationary relative to the rotation of the shaft 26 and the lower tubesheet disc valve by the lower inlet-outlet conduits 4t), 41', 42, 43',44', 45', and 46', which are welded to the lower cap closure 24 and havetheir upper ends connected, as by welding, to the manifolds a, b, c, d,e, and g, respectively, in the lower member 34 to provide communicationtherewith.

The upper and lower tube sheet disc valves 35 are identical inconstruction and, as shown in Fig. 4, each comprises a flat metal dischaving a plurality of circumferentially spaced circular openings 74-formed in a circular row adjacent its periphery. The disc is providedwith a collar 75 having a plurality of radially extending reinforcingribs welded to its bottom surface or cast integral therewith. The collar75 is keyed on the upper (lower) section of the shaft 26 to havelongitudinal movement therealong as well as rotative movement therewith,as by means of a set screw 76 slidably engaging in a longitudinal groove77 formed in the upper (lower) section of the shaft 26. A second collar78 is fixedly secured to the shaft 26 immediately beneath the collar 75to limit the inward movement of the disc as it moves longitudinally ofthe shaft 26. The disc 35, as well as the collar 75, are loosely fittedon the shaft 26 so that the disc valve can be moved slightly to conformto any change in the plane of the engaged surface of the stationarymember 34, due to unequal expansion and contraction.

The tube sheet disc 35 is so mounted on the shaft 26 that it slidablyengages the open bottom (top) end of the annular stationary member 34with the circular row of openings 74 vertically aligned with themanifolds a, b, c, d, e, f and g, so that each manifold will be incommunication with a group of the circular openings.

The upper and lower spring support discs 36 are identical inconstruction and, as shown in Fig. 4, each comprises a metal discmounted on the shaft and having a hub 79 provided with a plurality ofcircumferentially spaced radial ribs or webs welded to the under face ofthe disc to strengthen it. The hub is fixedly secured to the shaft, asby a set screw. A plurality of vertically extending circumferentiallyspaced coiled springs 37 are interposed between the tube sheet discvalve 35 and the spring support disc 36. In order to insure that thesprings 37 remain in proper position, they are mounted on and betweenshort stubs 36 extending upwardly from the disc 36 and shortcorresponding stubs 80 extending downwardly from the disc 35. Theconstruction and arrangement is such that the springs 37 will keep thedisc valve 35 evenly and firmly pressed into engagement with the undersurface of the annular stationary member 34.

The upper and lower flexible pipes 38, 3b, which connect the upper lowerend portions of the adsorbent material containing vessels 31 to theupper and lower distributive assemblages are identical in constructionand, as shown in Figs. 4 and 10, each comprises a thin walledcylindrical metal tube having the greater portion of its wall formed ina sinuous shape to give it flexibility, the outer cylindrical end ofeach tube is detachably secured to a nozzle 81 formed on the upper(lower) end portion of the vessel 33., as by strapping. The cylindricalinner end of the tube is provided with an integral flange 82. Theopening in the cylindrical inner end of the tube is aligned with one ofthe circular openings 74 formed in the upper lower) tube sheet discvalve 35 and the flange 32 is detachably secured to the outer surface ofthe disc valve, as by countersunk bolt-s, so that the inner surface ofthe disc wall will be smooth and uninterrupted (see Fig. 4).

To prevent the escape of gas between the rotating tube sheet disc valve35 and the mani olds in the member 34, sealing ring gaskets 33 areplaced at the juncture of the side walls of the member 34- and the discvalve 35. The ring gaskets 83 are wedged into annular troughs 84,secured, as by welding, to the outer surface of the side walls of themember 34. Each trough comprises an annular top (bottom) wall 85 and anannular side wall 86. The ring gaskets 83, preferably and as shown,comprise a plurality of annular strips of packing, generally rectangularin cross section and made of any suitable material, such as tetlon orsilica impregnated asbestos.

The seven manifolds a, b, c, d, e, f and g are sealed off from eachother by means of cross seals 87, each sealed into a recess 88 formed bythe adjacent end walls of the manifolds and a bottom plate 89 verticallyspaced from the open end of the manifolds (see Figs. 8 and 9). Eachcross seal is tightly wedged in its recess with its outer ends in tightengagement with the adjacent side walls of the annular seals 83 and withits bottom surface in sealing engagement with the upper (lower) surfaceof the tube sheet disc. In order for the outer ends of the cross sealsto engage the adjacent side walls of the annular seals 83, the portionsof the side Walls 71 and 72 of the member 34 which extend between eachpair of adjacent transverse members 73 are cut away, as indicated at 90,for a distance equal to the thickness of the seals 83 (see Fig. 9).

The widths of the manifolds a, b, c, d, e, f and g are substantially thesame as the internal diameters of the circular openings 74 in the tubesheet disc 35, so that each cross seal can effectively seal off one ofthe openings.

Each of the openings 74 formed in the upper tube sheet disc 35 is invertical alignment with a corresponding one of the openings 74 formed inthe lower tube sheet disc 35 and each of the cross seals 87 whichseparate the manifolds a, b, c, d, e, f and g formed in the upperstationary member 34 is in vertical alignment with a corresponding oneof the cross seals 37 which separate the manifolds a, b, c, d, e, ,t andg formed in the lower stationary member 34.

When the rotary disc valves 35 and the vessels 31 are stationary, theforegoing arrangement, in effect, divides the adsorbent materialcontaining vessels 31 into seven groups, with one group connected tocommunicate with the manifolds a, one group connected to communicatewith the manifolds b, one group connected to communicate with themanifolds 0, one group connected to communicate with the manifolds at,one group connected to communicate with the manifolds e, one groupconnected to communicate with the manifolds f, and one group connectedto communicate with the manifolds g. Each group of vessels 31, togetherwith the upper and lower manifolds with which they are in communicationform separate flow passages through the adsorber so that seven separate,distinct and continuous flows of fiuid may pass through the apparatus.Each flow entering the upper distributive assemblage by means of one ofthe inlet-outlet conduits 4t), 41, 42, 43, 44, 45, or 46, thence throughone of the groups of vessels 31 into the lower distributive assemblageand out through one of the inlet-outlet conduits 40', 41', 42, 43', 44',45', or 46. As the vessels 31 and the upper and lower disc valves 35rotate, each of the flows of fiuid will successively pass through thevessels 31. For convenience in description, each flow passage is calleda stage, in which either adsorption, activation, or purging takes place,depending upon the particular fluid flowing therethrough. Also, thevessels 31 are called zones, in which either adsorption, activation orpurging takes place, depending upon the particular fluid flowingtherethrough at a given time.

The silica gel containing vessels 31 are identical in con struction and,as shown in Figs. 10 and 11, each com prises an elongated hollow tubularmember 91 having a closed bottom end and an open upper end provided witha flanged collar 92 to which is secured, as by bolting, a removablecover plate 93.

A horizontally disposed annular disc 94 is mounted in the lower endportion of the member 91 and secured therein, as by welding, to form agas-tight joint between the outer peripheral edge of the disc and theside wall of the member 91. The lower annular disc 94 forms a supportfor an elongated annular fluid treating material container 95. Thecontainer 95 is removably mounted within the member 91, with its bottomend resting on the annular disc 94 and with the longitudinal open end ofthe container aligned with the opening in the disc.

The tubular member 91 has a tapered side wall for a purpose hereinafterto be described and is provided with upper and lower circular openings96 in which are secured, as by welding, the nozzles 81 to which theupper and lower flexible pipes-38 and 39 are secured.

A baflle member 97 is mounted in the space between the bottom of themember 91 and the annular disc 94, and an upper bafile member 98 issecured to the underside of the cover plate 93 and is removabletherewith. The upper and lower bafile members 98 and 97 are identical inconstruction and, as shown inFig. 10, each comprises a generallyelliptical-shaped flat sheet 99 extending upwardly (downwardly) from thebottom (top) of the member 91 to insure an even flow of fluid throughthe member 91; a side wall forming member 100; and insulatingmaterial.101 placed within the pocket formed by the members 99. and 100 and thebottom (top) wall of the member 91 (see Fig.

The containers 95 are identical in construction and, as shown in Figs.10 and 11, each comprises two concentric tubular screens 102, 103, heldin spaced-apart relation by a plurality of longitudinal radial fins 104,with the annular space between the screens closed at the bottom, as by aflanged annular plate 105. The mesh of the screens is such as to retaina granular adsorbent material 106 in the annular space between thescreens. In the instant case, the adsorbent material may be of anyadsorbent having characteristics substantially like silica gel or thegelof other activated hydrous oxides. Preferably silica gel isused.

Each of the containers 95 is closed at its top by means of concentrichoops or metal bands 107, 108 mounted on theconcentric screens 102, 103,and a cover plate 109 is detachably connected to the inner hoop or band108, as by screws, and having a depending annular flange 110 fittingbetween the hoops or bands 107, 108. A depend ing cylindrical fin 111 issecured to the flange 110 and projects downwardly between and below thehoops or bands 107, 1 08, and fits in slits 112 formed in the upper endsof the radial fins 104, all as shown in Figs. 10 and 11. Theconstruction is such that, as the silica gel settles down, leaving aspace between the top portion of the Wire screens devoid of silica gel,the fins 111 will prevent fluid from passing through the space.

Mounted Within the inner Wire screen 103 isan inverted. substantiallyconically shaped bafflemember 113. The baffle member 113 is closed atits apexwhich extends downwardlyto a point near the bottom of thecontainer. and-hasits upper peripheral edge suitablysecured to the band108, as by welding. Preferably, the battle member 113 is made of thinsheet metal.

When the container 95 is mounted within the hollow member 91, as shownin Fig. 10, the elongated annular space between the walls of the member91 andthe inverted conical baffie member 113 forms an elongatedfrusto-conically shaped duct which is annular in cross section. Theannular container, filled with silica gel, is positioned in the ductbetween the members 91 and 113 in such manner that it forms a. barrierextending longitudinally across the duct from top to bottom. The crosssectional areas of the duct at its top and bottom are sub-- stantiallyequal and the tapers of its side walls are such that a substantiallyuniform velocity is obtained on both sides of the barrier as fluidistransferred from the upstreamto the downstream side, regardless of thedirection offlow, thereby creating a substantially constant staticheadover the face of the barrier, resulting in a substantially uniformdistribution of thefluid throughout 10 the entire barrier area. Thus, itwill be seen that by using the members 91 and 113, as bafile members,the entire area is made use of with resultant increase in efliciency,capacity and economy.

Means may be provided so that the containers 95 which hold the adsorbentmaterial may readily be removed from and replaced in the vessels 31. Asshown, such means may comprise an opening 114 formed in the top of thevessel 20 having a cylindrical member 115 welded therein and providedwith a readily removable closure disc 116 secured in the upper end ofthe member 115, as by means of a split shear ring 117 bolted thereto andfitted into a circumferential recess 113 formed in the inner surface ofthe member 115, and an O-ring packing 119 mounted between the closuredisc 116 and the side wall of the member 115 to insure gastightness.

The flows of the various gases through the various stages of theadsorber and the auxiliary apparatus are schematically shown in Fig. 1.

As there shown, the natural gas from which water vapor and condensablehydro-carbons have previously been removed therefrom, is supplied underhigh pressure from about 800 p. s. i. to about 1000 p. s. i. by pipeline 5 and enters manifold a of the upper distributive assemblagethrough inlet-outlet conduit 40. From manifold a the gas passes throughopenings 74 formed in the upper tube sheet disc valve 35 and flexiblepipes 38 into the upper end portion of the group of vessels 31 whichare'at that. time in communication with the manifold a. The gas passesdown through the silica gel beds therein into the. bottoms of thevessels. The bafile members 113, in cooperation with the tapered sidewalls of the vessels 31, insure a substantially uniform-flow anddistribution of the gas through the silica gel beds, which adsorb someof the H28 content from the gas. From the bottoms of the vessels 31,,thenow partially HzS stripped gas passes. through outlet pipes 39 andopenings 74in the lower tube sheet disc valve 35 into the manifold a ofthe lower distributive assemblage.

From the lower manifold a of the-lower distributive assemblage, the gaspasses through inlet-outlet conduit 40 and pipe line 6 and intercooler 2to the second adsorption stage and enters manifold b of the lowerdistributive assemblage through inlet-outlet conduit 41'. the lowermanifold 12 the gas passes through openings 74 in the tube sheet discvalve 35 and inlet pipes 39 into the lower end portion of the group of.vessels 31 which are at that time in communication with manifold b. Thegas passes upwardly through the vessels 31 of the secondgroup andthrough the silica gel beds therein into the tops thereof, additionalHzS being adsorbed from the gas during its passage through the silicagel beds.

From the tops of the vessels 31 of the second adsorption group, the gaspasses through pipes 38 and openings 74 in the upper. tubesheet discvalve of the upper distributive assemblage into the upper manifold b.

From the upper manifoldfb the gas passes through inlet-outlet pipe 41and pipe line 7 and intercooler 2 to the third adsorption stage andenters upper manifold c of the upper distributive assemblage throughinlet-outlet conduit 42.

From the-upper manifold c the gas passes through openings 74 in the tubesheet disc valve 35 and inlet pipes 38'into the upper end portions ofthe group of vessels 31 which are at that time in communication withmanifold c. The gas passes downwardly'through the vessels 31 of thethird group and'through the silica gel beds therein into the bottomsthereof. The remaining HzS content of the gas being adsorbed during itspassage through the silica gel beds.

From the bottoms; of the vessels 31 of the third group, the gas passesthrough pipes 39 and openings 74 in the tube sheet disc valve 35' intothe lower manifold c. From the lower manifold c. the gas passes throughinlet-outletconduit 42' and pipe line 8' to thevarious:

points :of use.

From

The removal and recovery of the H28 from the beds of adsorbent materialis effected in the activation stage. The activation gas, a captive gas,preferably consisting substantially of H28, is heated in a heater 3,where its temperature is raised to from 250 F. to 400 F. From theheater, the heated activation gas passes through pipe line 9 andinlet-outlet conduit 45 into the lower manifold f of the lowerdistributive assemblage. From the manifold f the hot activation gaspasses through openings 74 in the lower tube sheet disc valve 35 andflexible pipes 39 into the lower end portions of the groups of vessels31 which are at that time in communication with manifold f. The gaspasses upwardly through vessels 31 of the activation group and throughthe silica gel beds therein into the tops thereof. As the hot passesthrough the adsorbent material it removes the adsorbed H23 therefrom.From the tops of the vessels 31, the hot H28 laden gas passes throughflexible pipes and openings 7 in the lower tube sheet disc valve 35 intothe upper manifold f. From the upper manifold f, the hot gas passesthrough inlet-outlet conduit 45 and pipe line 11 to the blower 4 and isrecycled by the blower through pipe line 11 and the heater 3, backthrough the activation stage. This recirculation process is continuous.

The recirculating captive stream of activation gas is allowed to becomehighly concentrated in desorbed products by passing directly from theactivation stage outlet back to the heater without any intermediatecooling.

After the concentration of H25 in the recycling activation gas hasreached a predetermined value of from about 80% to about 93% by volume,a portion thereof is continuously diverted and passes through pipe line19 to its point of use or storage.

In order to prevent slippage of activation gas, rich in desorbedproducts, into the outgoing stripped gas, and in order to preventdilution of the highly concentrated activation gas, a first purgingstage is provided ahead of and a second and third purging stage areprovided following the activation stage.

A portion of the recycling activation gas is diverted from pipe line 11for use as the purging gas in the first purging stage and passes throughpipe line 12 and inletoutlet conduit 46' into the lower manifold g ofthe lower distributive assemblage. From the manifold g the purging gaspasses through openings 74 in the lower tube sheet disc valve 35 andflexible pipes 39 into the lower portions of the group of vessels 31which are at that time in communication with manifold g. The gas passesupwardly through the vessels 31 of the first purging stage and throughthe silica gel beds therein into the tops thereof. As the purging gaspasses through the adsorbent material it removes the slippage naturalgas, thereby purging the beds. From the tops of the vessels 31 theeffluent gas consisting substantially of slippage gas from the firstadsorption stage passes through flexible pipes 38 and openings 74 in theupper tube sheet disc valve 35 into the upper manifold g. From the uppermanifold g the gas passes through inlet-outlet conduit to and pipe line13 back into pipe line and joins the natural gas being treated on itsway to the adsorber.

The gas used as the purging gas in the second purging stage is obtainedby continuously diverting a portion of the flow of the stripped naturalgas through pipe line 8 from the last adsorption stage of the adsorberthrough pipe line 14 to the blower 4'. From the blower 4 the purging gaspasses through pipe line 15 and inlet-outlet conduit 44' into the lowermanifold e of the lower distributive assemblage. From the manifold e thepurging gas passes through openings 74 in the lower tube sheet discvalve 35 and flexible pipes 39 into the lower end portions of the groupof vessels 31 which are at that time in communication with manifold e.The gas passes upwardly through the vessels 31 of the second purginggroup and through the silica gel beds therein into the tops thereof. Asthe purging gas passes through the adsorbent material it removes anyremaining activation gas or deposited vapors therefrom, thereby purgingthe beds. From the tops of the vessels 31, the efiluent gas consistingsubstantially of slippage activation gas passes through flexible pipes38 and openings 74 in the upper tube sheet disc valve 35 into the uppermanifold 2. From the upper manifold e the gas passes throughinlet-outlet conduit 44 and pipe line 17 into pipe line 10 and joins therecycling activation gas.

A portion of the purging gas flowing through pipe line 15 is divertedand passes through pipe line 16 and inletoutlet conduit 43' intomanifold d of the lower distributive assemblage. From the manifold d thepurging gas passes through openings 74 in the tube sheet disc valve 35and inlet pipe 39 into the lower end portion of the group of vessels 31which are at that time in communication with manifold d. The gas passesupwardly through the vessels 31 of the third purging group and throughthe silica gel beds therein into the tops thereof. The purging gasremoves any remaining activation gas and purges the silica gel bedsduring its passage through the beds of the third purging stage.

From the tops of the vessels 31 of the third purging stage the efliuentgas consisting substantially of slippage gas from the second purgingstage passes through outlet pipes 38 and openings 74 in the upper tubesheet disc valve of the upper distributive assemblage into the uppermanifold d. From the manifold d the gas passes through inlet-outletconduit 43, pipe line 18, and pipe line 13 to join the gas being treatedflowing through pipe line 5 on its way to the adsorber.

The gas being treated makes three passes through the adsorber, while theactivating gas and each of the purging gases each make a single passthrough the adsorber. For convenience in description, the stage of theadsorber through which the first adsorption passage of the gas beingtreated is made, is called the first adsorption stage, the stage throughwhich the second adsorption passage is made is called the secondadsorption stage, the stage through which the third adsorption passageis made is called the third absorption stage, the stage through whichthe hot gas used for activation passes is called the activation stage,the stage through which the first purging gas passes is called the firstpurging stage, the stage through which the second purging gas passes iscalled the second purging stage, and the stage through which the thirdpurging gas passes is called the third purging stage. Also, the vessels31 are called zones in which either adsorption, activation, or purgingtakes place, depending upon the particular fluid flowing therethrough ata given time. In addition, the heater 3 is called a heating zone.

In the particular embodiment of the invention illustrated, the valvediscs 35 and the vessels 31 are rotated clockwise, as viewed in Fig. 2,and at a rate such that the eflluent gas fiow from the purging stageswill be substantially volumetric with the slippage gas brought intothese stages as the vessels 31 are rotated; thus it will be seen that,as the valves 35 and the vessel 31 rotate, each of the vessels 31 willbe successively brought into communication with the manifolds g, f, e,d, c, b and a in the upper and lower distributive assemblages, so thateach vessel 31 will, in turn, become a first purging zone, an activationzone, a second purging zone, a third purging zone, a third adsorptionzone, a second adsorption zone, and a first adsorption zone.

Suitable stop valves are provided at any desired point in any pipe lineto provide means for controlling the flow of the various mediums throughthe various stages of the adsorber and the auxiliary apparatus.

From the foregoing, it readily will be seen that there has been provideda novel and improved cyclic adsorption process for treating fluids toremove and/ or recover particular constituents therefrom, in which aplurality of purging steps are employed so as to permit a highconcentration of desorbed products in the recycling captive activationgas stream by preventing the dilution of the activation gas by slippagegas, and alsoto prevent loss ofdesorbed products by slippage of theactivation gas into the outgoing eflluent stripped fluid; a processparticularly adapted for removing and/ or recovering 1-125 from naturalgas.

While some of the flows of fluid through the apparatus have beendescribed as entering the top distributive as semblage and flowingdownward to and out of the bottom distributive assemblage, obviously,the flows may be in either direction.

Obviously, too, the present invention is not restricted to theparticular embodiments thereof herein shown and described. 1

What is claimed is:

1. In the process of treating fluids to remove and/ or recover aparticular constituent therefrom involving the contact of adsorbentmaterial with the fluid to be treated with resultant adsorption of theparticular constituent by the adsorption material and the subsequenttreatment of the adsorption material with a heated medium to vaporizeandremove the particular constituent and thereby reactivate theadsorbent material for further contact with the fluid to be treated, theimprovement which comprises rotating a series of separated beds ofadsorbent material directly in succession and substantially continuouslyrelative to and through a first purging stage, an activation stage, asecond purging stage, and at least one adsorption stage; continuouslydirectinga flow of the fluid to be treated under high pressure and insuccession through the adsorption stages so that the particularconstituent thereof which is to be removed will be. adsorbed by theadsorbent material therein; continuously recycling a flow of captiveactivation medium through a heating zone and there heating the, captivemedium, then directly through said activation stage to desorb saidparticular constituent contained in the beds of adsorbent materialtherein, then directly back to said heating zone, whereby the recyclingcaptive activation medium will become highly concentrated in desorbedparticular constituent; continuously diverting a portion of therecycling activation medium and directing its flow through the firstpurging stage to remove all of the fluid being treated therefrom;continuously directing the flow of the efliuent fluid fromthe firstpurging stage into the flow of the fluid being treated on its way to thefirst adsorption stage; continuously diverting a portion of the flow ofthe effluent stripped fluid being treated from the last of saidadsorption stages and directing its flow through the second purgingstage to remove all of the activation medium therefrom and continuouslydirecting the flow of the eflluent fluid from the second purging stageinto the recycling activation medium; and continuously withdrawing aportion of the activation medium from its recycling path after it hasbecome highly concentrated in desorbed particular constituent, as thefinished product.

2. In the process of treating fluids to remove and/or recover aparticular constituent therefrom involving the contact of adsorbentmaterial with the fluid to be treated with resultant adsorption of theparticular constituent by the adsorption material and the subsequenttreatment of the adsorption material with a heated medium to vaporizeand remove the particular constituent and thereby reactivate theadsorbent material for further contact with the fluid to be treated, theimprovement which comprises maintaining at least one bed of adsorbentmaterial in each of a plurality of zones; continuously recycling a flowof a captive activation medium under high pressure through a heatingZone and there heating the captive medium, then directly through atleastone of said zones to desorb said particular constituent contained in thebedsof adsorbent material therein, then directly back to said heatingzone, whereby the recycling captive activation medium will become highlyconcentrated in desorbed particular constituent; continuously directinga first flow of a purging medium under high pressure through at leastanotheroneof said zones to purge the zone; continuously directing asecond flow of a purging medium under high pressure through at leastanother one of said zones to purge the zone; continuously directing theflow of the fluid being treated under high pressure through theremainder of said zones so that the particular constituent content ofthefluid will be adsorbed by the adsorbent material therein;periodically shifting the relative positions of the particular adsorbentmaterial and the particular flow of fluid in each of said zones so thateach zone becomes in succession a first purging zone, anactivation zone,a second purging zone and an adsorption zone; continuously diverting aportion of the captive activation medium from its recycling path for useas the first purging medium and continuously directing the flow of theeflluent fluid from the first purging zone back into the flow of thefluid being treated on itsway to the first adsorption zone; continuouslydiverting a portion of the stripped effluentfluid from the lastadsorption zone for use as the second purging medium and continuouslydirecting the flow of the effluent fluid from the second purging zoneinto the flow of the recycling captive activation medium; andcontinuously withdrawing a portion of the acti vation medium from itsrecycling path, after it has become highly concentrated in desorbedparticular constituent, as the finished product,

3. In the process of treating fluids to remove and/or recover aparticular constituent therefrom involving the contact of adsorbentmaterial with the fluid to be treated with resultant adsorption of theparticular constituent by the adsorption material and the subsequenttreatment of the adsorption material with a heated medium to vaporizeand remove the particular constituent and thereby reactivatetheadsorbent material for further contact with the fluid to be treated, theimprovement which comprises rotating a series of separated beds ofadsorbent material directly in succession and substantially continuouslyrelative to and through a first purging stage, an activation stage, asecond purging stage, a third purging stage, and a plurality ofadsorption stages; continuously directing a flow of the fluid to betreated under high pressure in succession through said adsorption stagesso that the particular constituent thereof which is to be removed willbe adsorbed by the adsorbent material as it passes through saidadsorption stages; continuously recycling a flow of captive activationmedium through a heating zone and there heating the captive medium, thendirectly through said activation stage to desorb said particularconstituent contained in the beds of adsorbent material therein, thendirectly back to the heating zone, whereby the recycling captiveactivation medium will become highly concentrated in desorbed particularconstituent; continuously diverting a portion of the recyclingactivation medium and directing its flow through the first purging stageto remove all of the fluid being treated therefrom and continuouslydirecting the flow of the eflluent fluid from the first purging stageinto the flow of the fluid being treated on its way to the firstadsorption stage; continuously diverting a portion of the flow of theefliuent stripped fluid being treated from the last adsorption stage anddirecting its flow through the second and third purging stages;continuously directing the flow of the effluent fluid from the secondpurging stage into the recycling activation medium; continuouslydirecting the flow of the eflluent fluid from the third' purging stageinto the flow of the fluid being treated on its way to the firstadsorption stage; andcontinuously withdrawing a portion of theactivation medium from its recycling path after it has become highlyconcentrated with desorbed particular constituent, as the finishedproduct.

4. In the process of treating fluids to remove and/ or recover aparticular constituent therefrom involving the contact of adsorbentmaterial with the fluid to be treated with resultant adsorption of theparticular constituent by the adsorption material and the subsequenttreatment of the adsorption ma terialwit h;a heated medium to vaporizeand remove the particular constituent and thereby reactivate theadsorbent material for further contact With the fluid to be treated, theimprovement which comprises maintaining at least one bed of adsorbentmaterial in each of a plurality of zones; continuously recycling a flowof a captive activation medium under high pressure through a heatingzone and there heating the captive medium, then directly through atleast one of said zones to desorb the particular constituent containedin the beds of adsorbent material therein, then directly back to saidheating zone, whereby the recycling captive activation medium willbecome highly concentrated in desorbed particular constituent;continuously directing a first flow of a purging medium under highpressure through at least another one of said zones to purge the zone;continuously directing a second flow of a purging medium under highpressure through at least another one of said zones to purge the zone;continuously directing a third flow of a purging medium under highpressure through at least another one or" said zones to purge the zone;continuously directing the flow of the fluid being treated under highpressure through the remainder of said zones so that the particularconstituent content of the fluid will be adsorbed by the adsorbentmaterial therein, periodically shifting the relative positions of theparticular adsorbent material and particular flow of fluid in each ofsaid zones so that each zone becomes in succession a first purging zone,an activation zone, a second purging Zone, a third purging zone, and anadsorption zone; continuously diverting a portion of the activationmedium from its recycling path for use as the first purging medium andcontinuously directing the flow of the effluent fluid from the firstpurging zone back into the flow of the fluid being treated on its way tothe first adsorption zone; continuously diverting a portion of thestripped eflluent fluid from the last adsorption zone for use as thesecond and third purging mediums; continuously directing the flow of theefliuent fluid from the second purging zone into the recyclingactivation medium; continuously directing the flow of the eflluent fluidfrom the third purging zone into the flow of the fluid being treated onits way to the first adsorption zone; and continuously withdrawing aportion of the activation medium from its recycling path after it hasbecome highly concentrated with desorbed particular constituent as thefinished product.

5. A method of removing and recovering H from natural gas from whichwater vapor and condensable hydrocarbons have previously been removedtherefrom comprising rotating a series of separated beds of adsorbentmaterial directly in succession and substantially continu ously relativeto and through a first purging stage, an activation stage, a secondpurging stage, and at least one adsorption stage; continuously directinga flow of the gas to be treated under high pressure and in successionthrough the adsorption stages so that the H23 content thereof will beadsorbed by the adsorbent material therein; continuously recycling aflow of captive activation gas consisting substantially of H28 through aheating zone and there heating the captive gas, then directly throughsaid activation stage to desorb the H28 contained in the beds ofadsorbent material therein, then directly back to said heating zone,whereby the recycling captive activation gas will become highlyconcentrated in desorbed HzS; continuously diverting a portion of therecycling activation gas for use as the purging gas for the firstpurging stage and directing its flow into the first purging stage andcontinuously directing the flow of the eflluent gas from the firstpurging stage into the flow of the gas being treated on its way to thefirst adsorption stage; continuously diverting a portion of the strippedeflluent gas from the last adsorption stage for use as the secondpurging gas and directing its flow into the second purging stage andcontinuously directing the flow of the eifluent gas from the secondpurging stage into the flow of the captive recycling activation gas onits way to be heated; and continuously withdrawing a portion of theactivation gas from its recycling path after it has become highlyconcentrated in HzS to a predetermined degree, as the finished product.

6. A method of recovering H25 from natural gas from which water vaporand condensable hydrocarbons have previously been removed therefromcomprising maintaining at least one bed of adsorbent material in each ofa plurality of zones; continuously recycling a flow of captiveactivation gas consisting substantially of H28, under high pressure,through a heating zone and there heating the captive gas, then directlythrough at least one of said zones to desorb the H28 contained in theadsorbent material therein, then directly back to said heating zone,whereby the recycling captive activation gas will become highlyconcentrated in desorbed H28; continuously directing a first flow of apurging medium under high pressure through at least another one of saidzones to purge the zone; continuously directing a second flow of apurging medium under high pressure through at least another one of saidzones to purge the zone; continuously directing the flow of the gasbeing treated under high pressure through the remainder of said zones sothat the H28 content of the gas will be adsorbed by the adsorbentmaterial therein; periodically shifting the relative positions of theparticular adsorbent material and the particular flow of fluid in eachof said zones so that each zone becomes in succession a first purgingzone, an activation zone, a second purging zone and an adsorption zone;continuously diverting a portion of the recycling activation gas for useas the first purging medium and continuously directing the flow of theeflluent gas from the first purging zone into the flow of the gas beingtreated on its way to the first adsorption zone; continuously divertinga portion of the stripped efllulent gas from the last adsorption zonefor use as the second purging medium and continuously directing the flowof the effluent gas from the second purging zone into the flow of therecycling captive activation gas; and continuously withdrawing a portionof the activation gas from its recycling path, after it has becomehighly concentrated in desorbed HzS as the finished product.

7. A method of recovering I-IaS from natural gas, from which water vaporand condensable hydrocarbons have previously been removed therefrom,comprising maintaining at least one bed of adsorbent material in each ofa plurality of zones; continuously recycling a flow of captiveactivation gas consisting substantially of H25, under high pressure,through a heating zone and there heating the captive gas, then directlythrough at least one of said zones to desorb the H28 contained in theadsorbent material therein, then directly back to said heating zone,whereby the recycling captive activation gas will become highlyconcentrated in desorbed H28; continuously directing a first flow of apurging medium under high pressure through at least another one of saidzones to purge the zone; con tinuously directing a second flow of apurging medium under high pressure through at least another one of saidzones to purge the zone; continuously directing a third flow of apurging medium under high pressure through at least another one of saidzones to purge the zone; continuously directing the flow of the gasbeing treated under high pressure through the remainder of said zones sothat the H25 content of the gas will be adsorbed by the adsorbentmaterial therein; periodically shifting the relative positions of theparticular adsorbent material and the particular flow of fluid in eachof said zones so that each zone becomes in succession a first purgingzone, an activation zone, a second purging zone, a third purging zone,and an adsorption zone; continuously diverting a portion of therecycling activation gas for use as the first purging medium andcontinuously directing the flow of the eifluent gas from the firstpurging zone into the flow of the gas being treated on its way to thefirst adsorption zone; continuously diverting a portion of the flow ofthe stripped eflluent gas from the last adsorption zone for use as thepurging medium for the second and third purging zones;

continuously directing the flow of the efiiuent gas from the secondpurging zone into the flow of the recycling captive activation gas;continuously directing the flow of the efl'luent gas from the thirdpurging zone into the flow of the gas being treated on its way to thefirst adsorption zone; and continuously withdrawing a portion of theactivation gas from its recycling path, after it has become highlyconcentrated in desorbed HzS, as the finished product.

8. A method of recovering HzS from natural gas from which water vaporand condensable hydrocarbons have previously been removed therefrom,comprising rotating a series of separated beds of adsorbent materialdirectly in succession and substantially continuously relative to andthrough a first purging stage, an activation stage, a second purgingstage, a third purging stage, and a plurality of adsorption stages;continuously directing a flow of the gas to be treated under highpressure in succession through said adsorption stages so that the H23content of the gas will be adsorbed by the adsorbent material as itpasses through said adsorption stages; recycling a flow of captive gasconsisting substantially of H28 through a heating zone and there heatingthe captive gas, then directly through said activation stage, thendirectly back to said heating zone, until the concentration of desorbedH25 in said captive gas has reached a highly concentrated degree;continuously recycling said highly concentrated captive gas streamthrough, said heating zone and said activation stage; continuouslydiverting a portion of the activation gas from its recycling path anddirecting its flow through the first purging stage and continuouslydirecting the flow of the effiuent gas from the first purging stage intothe flow of the natural gas on its way to the first adsorption stage ofthe adsorber; continuously diverting a portion of the flow of theefliuent stripped gas from the last adsorption stage and directing itsflow through the second and third purging stages; continuously directingthe flow of the efliuent gas from the second purging stage into therecycling activation gas; continuously directing the flow of theefiluent gas from the third purging stage into the flow 0f the naturalgas on its way to the first adsorption stage; continuously withdrawing aportion of the activation gas from its recycling path after it hasbecome highly concentrated with desorbed HzS, as the finished product.

References Cited in the file of this patent UNITED STATES PATENTS2,771,964 Miller Nov. 27, 1956

1. IN THE PROCESS OF TREATING FLUIDS TO REMOVE AND/OR RECOVER APARTICULAR CONSTITUENT THEREFROM INVOLVING THE CONTACT OF ADSORBENTMATERIAL WITH THE FLUID TO BE TREATED WITH RESULTANT ADSORPTION OF THEPARTICULAR CONSTITUENT BY THE ADSORPTION MATERIAL AND THE SUBSEQUENTTREATMENT OF THE ADSORPTION MATERIAL WITH A HEATED MEDIUM TO VAPORIZEAND REMOVE THE PARTICULAR CONSTITUENT AND THEREBY REACTIVATE THEADSORBENT MATERIAL FOR FURTHER CONTACT WITH THE FLUID TO BE TREATED, THEIMPROVEMENT WHICH COMPRISES ROTATING A SERIES OF SEPARATED BEDS OFADSORBENT MATERIAL DIRECTLY IN SUCCESSION AND SUBSTANTIALLY CONTINUOUSLYRELA-